Eyedrops and medications administered to the corneal surface of the eye are commonly dispensed from the familiar plastic squeeze bottle. The wall of the container is deformable inwardly to force the liquid medication through the open end of a nozzle-like dispensing tip in the well-known manner.
There are a number of now-familiar problems in using these eyedrop dispensers. For instance, it is difficult for the user to hold the dispenser tip steady while holding the eye open and the head tilted back in a steady position so the tip of the dispenser does not contact the eye. It is important to dispense the medication near the center of the eye; improper alignment can result in little if any medication reaching the eye. However, dispensers of the prior art must be held well inside the close focusing limit of the eye which is six to eight inches. Thus, it is not possible to view the tip of the dispenser at the critical position for dispensing drops onto the corneal surface.
There are instances in which medication administered to the eye must be carefully measured drop-by-drop for proper dosage prescribed by a physician. As an example, medications for the heart and other vital organs may be administered through eyedrops. Therefore, it is desirable, and often critical, to dispense medications to the eye with drop-by-drop accuracy.
Prior art devices intended to improve administration of eyedrop solutions to the eye have resulted in questionable improvements over the simple squeeze bottle that is still used for virtually all eyedrop solution containers. One modified dispenser of the prior art is disclosed in U.S. Pat. No. 4,550,866 to Moore (no relation). This patent discloses a dispensing device in which the nozzle has been modified to provide a multicolored target to aid the user in accurately focusing on the nozzle to position it relative to the eye when the medication is dispensed.
U.S. Pat. No. 4,257,417 to Gibilisco discloses a bottle holder having a nose rest and a bar with an opening through which the tip of the dispenser is mounted to slidably position and hold the dispenser over the eye.
Another prior art eyedrop dispenser sold under the name "Suredrop" includes a cup-shaped eyedrop guide that removably connects to the end of the dispenser. A special plug is unscrewed from the dispenser tip before use. Use of this device leads to contact between the user's fingers and the inside of the eye cup. Directions require thorough washing and sterilization with each use.
The minimal advantages of these prior art devices have not been sufficient to justify the additional manufacturing expense as well as effort and cost to the user. The simple squeeze bottle type dispenser continues to be the choice of virtually all eye care solution manufacturers.
The present invention avoids the disadvantages inherent in the prior art dispensers, while providing a novel close-focus capability for accurate visual positioning of the dispensing tip over the eye. As will be described in more detail below, the invention is used to controllably form a droplet of the liquid solution at the dispenser tip so that the user may visually observe the exact moment when the droplet will be released. This close-focus dispenser also enables the user to accurately align the droplet with the center of the eye. The present invention, as a result, eliminates significant negative factors associated with .use of prior eyedrop dispensers. These disadvantages include: (1) as previously emphasized, the inability of the human eye to focus upon an object as close as the dispensing tip must be for effective use, and (2) anticipation of the subsequent shock experienced by the user when the released drop, surprisingly strikes the sensitive corneal surface of the eye. The latter effect produces the familiar involuntary flinch response and squeamish feeling of anticipation that users commonly experience, which frustrates the process of administering eyedrop solutions comfortably and effectively.
The foregoing deficiencies of the prior art are overcome by the present invention which enables the user to visually observe and carefully control progressive development and release of the droplet, while also enabling precise optical alignment of the dispensing tip over the center of the cornea for accurate administration of the solution.
In addition, the present invention may be readily adapted to existing production equipment at very little expense. Only slightest modification of existing dispenser molding equipment is required. No changes are required to the basic geometry of the nozzle or dispensing tip components, nor to other components of the otherwise conventional plastic squeeze bottle dispenser. This avoids use of more expensive and bulky external dispenser guides and the resulting sanitation problems that may be associated with their use.